It's really important to establish a boundary or hula hoop for yourself. This can be achieved by asking your horse to back up or move out of your space. You might have to use a stick and string to reinforce. Most of the time I just have to wave my hands in front of a horse and force him to back off. You start by tapping the air with the stick, if they don't take a step backward, continue by tapping the lead rope and tap their front hooves with the toe of your boot. As soon as they take even one step back, release the pressure, and praise them, then ask again. I only allow a horse to come into my circle when they are asked to do so. This takes consistent work but it really will give you the results You're looking for. Ground work, manners, getting their feet to move, will clarify boundaries and result in a more respectful horse.